NPRD and EPRD Libraries
The Prediction module supports both the 2011 and 1995 publications of Nonelectronic Parts Reliability Data (NPRD), which are referred to as NPRD-2011 and NPRD-95. In addition, the Prediction module supports the 1997 publication of Electronic Parts Reliability Data (EPRD), which is referred to as EPRD-97.
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While the two NPRD Libraries are always available, the EPRD Library is available only when the 217Plus and/or PRISM model is licensed.
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These databooks are electronic databases of failure rates published by the RIAC (Reliability Information Analysis Center). While reliability prediction standards like MIL-HDBK-217 contain mathematical models that are derived from empirical field failure data, these databooks contain historically observed field failure rates for commercial quality components and other part types not addressed by MIL-HDBK-217 that you can use for unsupported part types. For example, when a model does not support a failure rate calculation for a part in your system design, you can search the NPRD and EPRD Libraries to locate and insert a failure rate for this part. In the RBD module, you can also search the NPRD and EPRD Libraries to locate and insert an NPRD or EPRD part as a block in a block diagram.
The NPRD Libraries supply failure rates for a wide variety of component types, including mechanical, electromechanical, and electronic parts, concentrating on parts not covered by MIL-HDBK-217. For example, it includes failure rates for actuators, bearings, brakes, clutches, connectors, gears, inductive components, optoelectronic devices, pumps, relays, seals, solenoids, splines, springs, and valves. The newer NPRD 2011 Library contains failure rates for more than 81,000 parts!
The EPRD Library supplies both merged and single line item failure rates obtained from field usage of both commercial and military components, including integrated circuits, discrete semiconductors, resistors, capacitors, and inductors/transformers.
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The units for all failure rates for EPRD parts are failures per million calendar hours rather than failures per million operating hours.
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When you use an NPRD Library or the EPRD Library, you specify part search criteria. Search results provide summary and detailed data sorted by part type, quality level, environment, and data source. From the results, you can choose to insert the part with the failure rate you want to use in your analysis. For an EPRD part, you can choose to insert either a merged failure rate for all parts meeting the specified criteria or the failure rate associated with any single part meeting these criteria.
For NPRD and EPRD part insertion information, see: